| 摘要 |
PURPOSE:To form an Image pattern with, for example, ground pattern. etc., on the background of an original image transferred on a transfer-sheet with inexpensive and simple constitution. CONSTITUTION:Toner density attached on a photosensitive material 6 is varied based on the light quantity of an exposure lamp 3, electrification quantity on the photosensitive material 6 by an electrifier 7, and the developing bias of a developing roller 9. A signal from a signal generating means 32 and a PWM signal whose pulse width is decreased or increased gradually corresponding to a cycle set on a timer means 33 are applied to, for example, a high voltage electrification means 22. The high voltage electrification means 22 varies voltages applied to the wire for corona discharge and the grid of the electrifier 7 so as to be proportional to the pulse width of the PWM signal, and varies the electrification quantity on the photosensitive material 6. The electrostatic latent image of a white paper original is formed on the photosensitive material 6, and is made into a visual image by toner, and when a toner image is transferred on a transfer sheet, the toner image with low density is formed at an area with low electrification potential, and the toner image with high density at an area with high electrification potential. |
